Chapter 20, Problem 20.22CP

(a)

Interpretation Introduction

Interpretation:

On the periodic table, the position of the given element has to be located.

Explanation of Solution

Given electronic configuration,

$\left[\text{Ar}\right]\text{3}{\text{d}}^{\text{7}}\text{4}{\text{s}}^{\text{2}}$

Electron filling concepts in orbitals:

• Electrons first occupy the orbitals with lower energy than the orbitals with higher energy (Aufbau principle).
• An orbital can be occupied only by two electrons having opposite spins (Pauli exclusion principle).
• Each electron fills each orbital till it is half filled, when they are degenerate orbital (Hund’s rule).

The order of electrons filling in a multi-electron atom is given as follows,

Figure 1

The order of orbitals in their increasing energy is given by

$\begin{array}{l}1s\text{<}2s\text{<}2p\text{<}3s\text{<}3p\text{<}4s\text{<}3d\text{<}4p\text{<}5s\text{<}4d\text{<}5p\text{<}6s\text{<}4f\text{<}5d\text{<}6p\\ \text{<}7s\text{<}5f\text{<}6d\text{<}7p\end{array}$

Calculate the total number of electrons in the given electronic configuration and identify the element

$\begin{array}{l}\left[\text{Ar}\right]\text{3}{\text{d}}^{\text{7}}\text{4}{\text{s}}^{\text{2}}\\ \\ \text{18}\left(\text{from}\text{Ar}\right)\text{+}\text{9}\text{=}\text{27}\text{electrons}\\ \\ \text{given}\text{atom}\text{is}\text{neutral,}\text{so}\text{Z}\text{=}\text{27}\text{for}\text{Co}\end{array}$

The position of the given element on the periodic table is given below:

Figure 2

(b)

Interpretation Introduction

Interpretation:

On the periodic table, the position of the given element has to be located.

Explanation of Solution

Given electronic configuration,

$\left[\text{Ar}\right]\text{3}{\text{d}}^{\text{5}}{\text{4s}}^{\text{1}}$

Electron filling concepts in orbitals:

• Electrons first occupy the orbitals with lower energy than the orbitals with higher energy (Aufbau principle).
• An orbital can be occupied only by two electrons having opposite spins (Pauli exclusion principle).
• Each electron fills each orbital till it is half filled, when they are degenerate orbital (Hund’s rule).

The order of electrons filling in a multi-electron atom is given as follows,

Figure 1

The order of orbitals in their increasing energy is given by

$\begin{array}{l}1s\text{<}2s\text{<}2p\text{<}3s\text{<}3p\text{<}4s\text{<}3d\text{<}4p\text{<}5s\text{<}4d\text{<}5p\text{<}6s\text{<}4f\text{<}5d\text{<}6p\\ \text{<}7s\text{<}5f\text{<}6d\text{<}7p\end{array}$

Calculate the total number of electrons in the given electronic configuration and identify the element

$\begin{array}{l}\left[\text{Ar}\right]\text{3}{\text{d}}^{\text{5}}{\text{4s}}^{\text{1}}\\ \\ \text{18}\left(\text{from}\text{Ar}\right)\text{+}\text{6}\text{=}\text{24}\text{electrons}\\ \\ \text{Given}\text{element}\text{is}\text{neutral,}\text{so}\text{Z}\text{=}\text{24}\text{for}\text{Cr}\end{array}$

The position of the given element on the periodic table is given below:

Figure 3

(c)

Interpretation Introduction

Interpretation:

On the periodic table, the position of the given element has to be located.

Explanation of Solution

Given electronic configuration,

$\left[\text{Kr}\right]\text{4}{\text{d}}^{\text{2}}\text{5}{\text{s}}^{\text{2}}$

Electron filling concepts in orbitals:

• Electrons first occupy the orbitals with lower energy than the orbitals with higher energy (Aufbau principle).
• An orbital can be occupied only by two electrons having opposite spins (Pauli exclusion principle).
• Each electron fills each orbital till it is half filled, when they are degenerate orbital (Hund’s rule).

The order of electrons filling in a multielectron atom is given as follows,

Figure 1

The order of orbitals in their increasing energy is given by

$\begin{array}{l}1s\text{<}2s\text{<}2p\text{<}3s\text{<}3p\text{<}4s\text{<}3d\text{<}4p\text{<}5s\text{<}4d\text{<}5p\text{<}6s\text{<}4f\text{<}5d\text{<}6p\\ \text{<}7s\text{<}5f\text{<}6d\text{<}7p\end{array}$

Calculate the total number of electrons in the given electronic configuration and identify the element

$\begin{array}{l}\left[\text{Kr}\right]\text{4}{\text{d}}^{\text{2}}\text{5}{\text{s}}^{\text{2}}\\ \\ \text{36}\left(\text{from}\text{Kr}\right)\text{+}4\text{=}\text{40}\text{electrons}\\ \\ \text{given}\text{element}\text{is}\text{neutral,}\text{so}\text{Z}\text{=}\text{40}\text{for}\text{Zr}\end{array}$

The position of the given element on the periodic table is given below:

Figure 4

(d)

Interpretation Introduction

Interpretation:

On the periodic table, the position of the given element has to be located.

Explanation of Solution

Given electronic configuration,

$\left[\text{Xe}\right]\text{4}{\text{f}}^{\text{3}}{\text{6s}}^{\text{2}}$

Electron filling concepts in orbitals:

• Electrons first occupy the orbitals with lower energy than the orbitals with higher energy (Aufbau principle).
• An orbital can be occupied only by two electrons having opposite spins (Pauli exclusion principle).
• Each electron fills each orbital till it is half filled, when they are degenerate orbital (Hund’s rule).

The order of electrons filling in a multielectron atom is given as follows,

Figure 1

The order of orbitals in their increasing energy is given by

$\begin{array}{l}1s\text{<}2s\text{<}2p\text{<}3s\text{<}3p\text{<}4s\text{<}3d\text{<}4p\text{<}5s\text{<}4d\text{<}5p\text{<}6s\text{<}4f\text{<}5d\text{<}6p\\ \text{<}7s\text{<}5f\text{<}6d\text{<}7p\end{array}$

Calculate the total number of electrons in the given electronic configuration and identify the element

$\begin{array}{l}\left[\text{Xe}\right]\text{4}{\text{f}}^{\text{3}}{\text{6s}}^{\text{2}}\\ \\ \text{54}\left(\text{from}\text{Xe}\right)\text{+}\text{5}\text{=}\text{59}\text{electrons}\\ \\ \text{given}\text{element}\text{is}\text{neutral,}\text{so}\text{Z}\text{=}\text{59}\text{for}\text{Pr}\end{array}$

The position of the given element on the periodic table is given below:

Figure 5